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The short of it..

IF YOUR EGR VALVE IS HOOKED TO VACUUM YOUR ENGINE WILL NEVER RUN RIGHT!!!!

I just wanted to post this real quick. I have a tendency to never get around to posting information so I at least want to put out what was the cause of my MAJOR idle issue with my 3 stage vtec JDM d15b/d15z7 swap into a 99 EK chassis (LX) using the JDM manual tranny ecu.

If your d15 swap won't idle, you can't time it, and nothing seems to work... If you are pulling your hair out wondering if the problem is the ECU (since you swapped it) the different IACV (3 -> 2 wire swap ) somewhere in your added wiring, the crank sensor, the map sensor, the TP, the different throttle body or any other thing you MAY have changed/altered from known good parts or you don't know if your ECU can use them effectively...

If you are at this point and your EGR VALVE is still hooked to vacuum STOP!!!!
Stop stop stop stop stop stop!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! !!!!!!!!!!!!!

Maybe I am the only person who would assume that since there is an electrical connector on the EGR valve and a vacuum port... you just plug in the harness and hook the vacuum port to the manifold and forget about it.

Maybe I am the only person doing this swap that made that logical but INCORRECT assumption. According to the Haynes manual for American Civics, section 6-19, the EGR system consists of one electrical component for a manual transmission setup but TWO ELECTRICAL COMPONENTS for engines mated to a CVT.

If you are like the majority of people attempting this swap and the information out there is correct, your engine was probably mated to a CVT tranny in Japan... (that's kind of funny, wonder what the kids will look like)... anyway this means that you have the EGR valve/system that is not a stand-alone unit. If this is the case and IF YOUR EGR VALVE IS HOOKED TO VACUUM YOUR ENGINE WILL NEVER RUN RIGHT!!!! one more time...

IF YOUR EGR VALVE IS HOOKED TO VACUUM YOUR ENGINE WILL NEVER RUN RIGHT!!!!

That is all that I have the time to write for now... I will edit this original post as I get the time... for the most part all the info out there is correct as far as wiring and such is concerned... but... you CAN use a 3-wire IACV... at least I have been... I am getting a code now so maybe it was a mistake and I cooked something... I don't think so though...

I can get into specifics later but the short is this... the 2 wire is a normally closed valve (the engine dies without the harness connected... the 3 wire is a normally open valve (the engine races without the harness connected... but the 3 wire has an adjustment on right side (2 screws and grooved slots) you will have to remove both screws turn the metal adjustment plate PAST the grooved slots (if I remember correctly it is about an hour or two past in the clockwise direction) and put ONE screw back in (both didn't fit in my application)... I used 2 of the 3 wires ONLY and the wires are pinned in the correct location for a 2-WIRE SETUP... essentially I made the 3 wire IACV a normally closed valve and set it to open with the ECU's signal... it is/can be VERY difficult to tune in ... set your base idle first on your TB... I don't think the 3 wire valve modified this way has the same potential flow as the 2 wire but it has been working for me... I only get an IACV code now when the engine has warmed up... I notice the problem in the low RPM range as the car feeling jerky (jack hammer) at low RPM range... I think I can eliminate this... anyhow that is all for now...

DISCLAIMER: All information is for educational purposes only. If you attempt to perform any of the above and anybody or anything (your car tools ECU etc.) are injured in the process it has happened because you used your own judgement and decided to attempt something knowing it is experimental only!!!!